Control mechanism for focal plane shutters



July 11, 1939 J. MIHALYI CONTROL MECHANISM FOR FOCAL PLANE SHUTTERS 'Original Filed Nov. 13, 1937 5 Sheets-Sheet l JOSEPH MIHALYI INVENTOR ATTORNEYS B ODDIICDDD July 11, 1939. J. MIHALYI CONTROL MECHANISM FOR FOCAL PLANE SHUTTERS S Sheets-Sheet 2 Original Filed Nov. 15, 1937 FIG.5.

JOSEPH MIPL ILYI INVENTOR K 135 149 ATTORNEYS July 11, 1939. J H Y. 2,165,403

CONTROL MECHANISM FOR FOCAL PLANE SHUTTERS Original Filed Nov. 13, 1937 5' Sheets-Sheet 5 FIG],

JOSEPH MIHALYY INVENTOR ATTORNEYS July 11, 1939.

J. MIHALYI CONTROL MECHANISM FOR FOCAL PLANE SHUTTERS Original Filed Nov. 13, 1937 5 Sheets-Sheet 4 FIG. 11.

FIGJZ.

JOSEPH MHMLYY I INVENTOR may f/wm i4 WE n u n ATTORNEYS July 11, 1939. MlHALYl 2,165,403

CONTROL MECHANISM FOR FOCAL PLANE SHUTTERS Original Filed Nov. 13, 1937 5 Sheets-Sheet 5 JOSEPH MIHALYY INVENTOR AT'TORNEYS' Patented July 11, 1939 UNITED STATES PATENT OFFICE CONTROL MECHANISM FOR FOCAL PLANE SHUTTERS Original application November 13, 1937, Serial N0. 174,443. Divided and this application July 20, 1938, Serial No. 220,304

14 Claims.

This invention relates to photography and more particularly to control mechanisms for shutters of the focal plane type.

One of the objects of my invention is to provide a focal plane shutter so arranged that the is moved into an operative position each time the first curtain is released. Still another object,

of my invention is to provide a floatingrelease lever pivotally mounted in such a way that it may be swuns'toward the second curtain release and an adjustable stop in such a manner that when one end strikes the adjustable stop, the other end will release the tripping latch for the second curtain, thereby permitting the second curtain to follow the first after a predetermined time interval. Other objects will appear from the following specification, the novel features being.particularly pointed out in the claimsat the end thereof.

This application is a division of my copending application for Focal plane shutter, Serial No. 174,443, filed November. 13, 1937.

Coming now to the drawings wherein like reference characters denote like parts throughout:

Fig. 1 is a top plan view of a camera equipped with a shutter constructed in accordance with this invention.

Fig. 2 is an enlarged fragmentary vertical fictional view approximately on line 2-2 voi! Fig. 3 is a rear elevation on a reduced scale, of the camera shown in Fig. 1, part of the back being broken away to show some interior parts.

Fig. 4 is a fragmentary enlarged part section and part plan view showing some of the operating parts in wound position, ready to be released.

Fig. 5 is a similar view showing the relation of the parts after the operating button has been depressed.

Fig. 6 is a fragmentary enlarged section and part elevation approximately on line 66 of Fig. 4.

Fig. 7 is a plan view of a group of operating parts, set for a shutter speed of second.

Fig. 8 is a view similar to Fig. 7 showing the parts set for operation atl second.

Fig. 9 is an enlarged fragmentary section on line 8-! ofFigrS.

Fi 10 is a detail of, a clutch member.

Fig. 11 is an enlarged part plan and part sectional view of a group of parts just after the release button has been depressed for an exposure shorter than ,5 second.

Fig. 12 is a view similar to Fig. 11 showing the delayed exposure action mechanism.

Fig. 13 is a vertical section of the retarding gear train assembly.

Fig. 14 is a fragmentary section on the line l4--l4 of Fig. 7.

Fig. 15 is a fragmentary plan view of a latch member and associated parts, the shutter being wound.

Fig. 16 is a plan view of the same parts shown in Fig. 15, with additional exposure regulating members, the shutter being unwound or released.

Flg. 17 is a diagrammatic elevation of the shutter curtains when the shutter is wound.

Fig. 18 is a similar view showing the shutter slit or established aperture passing over the exposure aperture of a camera; and

Fig. 19 is also a diagrammatic elevation similar to Figs. 17 and 18, the shutter curtainsoccupying the relation they will assume as the curtain apertures are in register with the exposure aperture.

Fig. 20 is a diagrammatic top plan view showing the relation of the shutter members and the relation of the roller supports.

Brief general description second curtain moves with the first across the exposure aperture to make an exposure. The shutter curtains and film may be rewound together eliminating double exposures. The shutter may be released only when the shutter is completely wound. A single retarding device may be used either for delaying the start of an exposure or delaying the duration of an exposure or both. At each operation of the shutter as a fresh area of film is presented for exposure there is a counter which indicates the number of exposures made.

While in the illustrated embodiment a "miniature type of camera is shown and described obviously any size of film and camera can be .used. Since the camera button or trigger is re- RC has an edge E adapted to cooperate with' leased rather than pushed to make an exposure as in the known types of cameras there is but little chance of shaking the camera.

Showing in drawings In view of the small size of the parts the drawings show, mostly on enlarged scales, many of the parts. It should be pointed out that in many figures certain parts have been omitted to avoid complication and so that the operations may be more easily understood. Certain supports and parts omitted in some instances are shown in other figures to illustrate their particular functions. Therefore, the figures of the drawings may not be complete each in itself but the structure necessary to understand the invention is present in one figure or another.

Illustrated embodiment The shutter embodying the present invention is illustrated as applied to a camera of the miniatureftype, which is shown in plan view in Fig.- and which has a body 28 adapted to hold roll film, a focusing lens assembly 2i, a supply spool 22 and a windup spool 23 for the film F which has edge perforations P (Fig. 3).

Built up from the top 24 of the camera body I 28 is a chamber or housing 25 that contains parts of'the shutter mechanism and timing controls, and which, on "its top 28, has a disc 21 by which the operator may select certain speeds, and a second disc 28 for selecting other and slower speeds. Anexposure recorder or counter, indicated generally by the numeral 28, islOcated in the center of the housing 25. Suitable range and view finders 30, with adjusting and compensating controls, indicated 3|, also may be arranged in the housing 25, but these units'form. no part of the present invention.

Curtain structure When the shutter is wound, both curtains that constitute the shutter proper are rolled around their respective rollers, hereinafter designated as windup rollers, which receive the curtains in the wound and set position.

These curtains are shown, somewhat diagrammatically, in Figs. 1'7, 18, and 19, and are designated FC to represent the front curtain, or the one "nearest the camera lens, and RC, the curtain nearest to the camera back. The curtain FC has an aperture CA, equivalent to the exposure frame A of the camera, while the curtain aperture CA to produce a variable width movable slit as will be presently described. Curtain FC has a foot roller 34 which is constantly urged counterclockwise to wind the curtain thereon (viewed from the top of the camera) by an internal spring, not shown, in the manner commonly employed in certin shutters, whereby the curtain is carried across the exposure frame of the camera when released. Curtain RC is similarlayspulled and rolled around another foot roller At the left side of the exposure aperture A of the camera is a shaft 48 to which narrow spools 38 are pinned (Figs. 2 and 18.) These spools are adapted to receive ribbons R, attached to ourtain RC 'at its edge E. The lower spool 38 carried a clutch. disc 4| adapted to frictionally engage a toothed clutch member 42 that projects r into a-rccess in the windup roller 38. The latter is adapted to receive the curtain FC when the winding or setting mechanism is operated. A y

shaft 48 and spools 39, when wound, against ball bearing 43Jat the top of the lower recess in roller 38 carries the weight of this roller so that it may rotate with minimum friction. The upper end of .roller 38 also is recessed for balls 45, which constitute an anti-friction bearing between upper spool 39 and the roller 38.

A holding ratchet 41, having two teeth or shoulders 48 and 50 (see Figs. 4, 5, and 11) is fixed to the top of shaft 40. A latch, later to be described, cooperates with this ratchet to hold or release the rear curtain BC by reason of the connection of the latter to the shaft 48 through the spools 38. n

Film wind and shutter setting This crank is mounted on a shaft 44 that extends through the camera back and carriesa ratchet 38, constantly engaged by a pawl 31, the latter being mounted on the back of a crown gear 32. This crown gear, being free on the shaft 44, will be turned counterclockwise whenever the crank 33 is swung to the position shown in broken lines in Fig. 3. One or more of such movements accomplishes a complete winding of the shutter curtains, and so fully sets the shut ter. This structure is more completely described in my copending application Serial No. 137,483 filed April 17, 1937.

The crown gear 32 meshes with a spur gear 52 (Figs. 2 and 3) that is pinned to a shaft 53. Sprockets 54, spaced to engage perforations P in the film F, are also attached to shaft 53. These elements are so proportioned that movement of the crank 33 above mentioned will cause the shaft 53 to make one complete revolution, and the film F will be advanced one frame. The film windup spool 23 is driven from gear 52 through a gear train 55 and an overrunning clutch, not shown, to maintain the required film Shutter mechanism The shaft 53 (Figs. 2, 4) has an extension 58 to which is fixed a holding ratchet 51, having a shoulder 58. A pawl 80, pivoted at 82, is normally held in engagement with shoulder 58 by a spring 81. The pivot 82 is a stud set into and extending downwardly from a gear 83, this gear being freely revoluble on shaft 56, so that if this ,shaft and the ratchet 51 are rotated clockwise (Fig. 4) as they will be whenever the winding lever 33 is moved as in Fig. 3, the pawl and the gear 83 are rotated clockwise also, and gear 83, through idler gears 84 and 85 on a stud 88, drives gear 5| andtherefore the curtain roller 38 'in a clockwise direction to wind up both the front curtain FC directly, and the rear curtain RC through the friction disc clutch 4|, into the relative positions diagrammatically illustrated in Fig. 17. To this end, a lever 88, hereinafter referred to as a latch lever (Fig. 11), is pivoted at 81 and has the shoulder 58 on ratc et 41 and thus to hold the rear curtain RC from passing over the exposure aperture A.

The end of the latch lever 66 shown at the left in Figs. 2, 4, and II is turned up and toward the right and has a rounded portion 69. The lower portion of lever 66 has a slot 10, and a stationary pin 1I serves as a guide and a stop for limiting the swing of said lever. a

Above lever 66 is a part 12, hereinafter designated as the release lever, and this part is piv-' oted at 13. The-function of lever 12 is primarily to disengage the latch lever 66 from the shoulder 50, but several other functions and movements of parts are accomplished as the release lever swings to left and right about the-pivot 18.-

Operating button for setting slit The operating button or trigger, 14 which is conventiently located so that it may be pressed by the operator's left index finger, is slidably mounted (Fig. 1, 3, and 6) at the upper left corner of the camera. A downward pressure on this trigger swings a bellcrank 15 about a pivot 16, against the action of a spring 15a, and through a link 11 that connects said bellcrank with an upturned lug 18 on'the release lever 12,

pulls the latter toward the left and into the position indicated in Fig. 5. At this point a lug 19 on lever 12 rests against shoulder 49 on holding ratchet 41, so that the latter cannot move counterclockwise even though latch 66 is disengaged from shoulder 50, as it is immediately, through means to be described. Ratchet 41, which is substantially integral with spools 39, cannot turn, and therefore curtain RC cannot move across exposure aperturev A, until the operator lifts his finger from button 14. The spring 15a tends at all times to raise the button 14, by acting on bellcrank 15 (Fig. 6) 'and therefore tends to move release lever 12 to the right.

Ratchet 51, fixed to shaft 56, although turned clockwise by the movement of winding crank 89 as previously described, cannot move counterclockwise at any time, because'of a pawl pivoted on the underside of the camera top 24, that constantly engages a ratchet 8| also fixed to shaft 56 (Fig. 2). When lever 12 is moved to the positioniof Fig. 5, a lug 82 on said lever strikes the right end of pawl 60, and the gears 63, 64, 5|, and- 66, tend to rotate under the pull of the foot roller 34 to permit the curtain FC to pass over the aperture A to the roller 34. However, a pawl 83, pivoted at 84, moves to the left under the pressure of a spring 88a and engages a ratchet 85 that is fixed to gear 64. Thelatter, and therefore curtain FC, cannot move, even though pawl 60 is free from shoulder 58 of ratchet 51.

Trigger-shutter release As'the operator raises his finger from trigger 14, the spring 1511, through bellcrank 15 and link 11, moves release lever 12 toward the right,-or counterclockwise about its pivot 13, unit a prong 86 on said lever strikes a lug 81 on pawl 83 and disengages the latter from ratchet 85. The curtain PC is then free to be rolled onto the foot roller", and when it has moved a predetermined distance, to establish the exposure slit, the curtain RCis also released and said slitpasses over the exposure aperture A. The means for determining'the width of the slot, which may be controlled manually or by a photroni c. selector,

ing set forth at this time.

will now bedescribedthe manual means only be- 75 strikes the end 69 of latch Speed selector Referring first to Figs. #2, and 7, the primary speed selector starts with a fevoluble indexed disc 21. This disc has a stud 88 extending through the top 26 of housing 25, (Fig. 2) to which is fixed a disc 89 having a cam slot 90 best shown in Fig- 7. A pin 9I, cooperating with this slot, is fixed in an arm 92, hereinafter mentioned as the selector member, pivoted at 93. The free end of selector member 92 .may engage (Fig. 11) an upturned forked end 94 on a lever 95, hereinafter designated as an interceptor, that is pivoted at 96 on a bellcrank 91. The latter may be rotated about its own pivot 99 against the action of a spring 91a. This spring constantly tends to rotate the bellcrank 91 clockwise (Figs. 15 and 16) about the pivot 68 and thus to press a pin 99 that projects downward from one end of said bellcrank, into contact with the periphery of a cam I00, which is attached to the gear 63. A square pin IOI, Figs. 11 and 14, (an extension of pawl pivot 62) extends downwardly below the gear 68 and into the plane of the latch 66. The left end I02 of the interceptor member lies in the plane of lug 69 on latch member 66.

When theoperator presses the button 14, the release lever 12 disengages the pawl 60 from the ratchet 51, while the shoulder of latch 66 is holding ratchet 41 and curtain RC from unwinding or passing across the exposure aperture A. This movement permits pawl 83 to engage ratchet 85 and hold curtain FC from unwinding. When the trigger 14 is released, lever 12 moves toward the it, so that the-opposite end of the bellcrank 91, p

on which interceptor lever 95 is mounted, moves toward the back of the camera. Member 95 is thus carried bodily in the same direction, but as the forked end 95 thereof strikes the pointer, the movement of the end 94 is arrested and the opposite, end I02 then swings toward the back of the camera and strikes the upturned end 69 of latch 66. The contact of pin 99 with cam I60 has then stopped the curtain FC for an instant, but as soon as end I02 of member 95 strikes lug 69 as aforesaid, the latch 661s swung'about its pivot 61 in a counterclockwise direction and the shoulder 68 slips off from shoulder 50 on holding ratchet 41, thus releasing shaft. The curtains RC and FC then move together across the aperture A of I the camera.

The combined effects of the .position of pointer I18 and the contour of cam I00 determine the point at which the end I02 of interceptor 95 66, and hence establishes the "slit or distance between edge E of curtain RC and edge G of curtain FC.

Automatic exposures by the simultaneous regase of both curtains from {the fully wound position, or from the ,relatrve positions of Figs. 4 and 17.\'Ihe proportions of the parts above described are such that when the selector 92 has been moved to the & location,

it will be close against the forked end 94 of the member. 95, so that the end 94 will not move at all when the bellcrank-91 begins to turn about the pivot 98. The result of this is that pawl 83 is disengaged from the ratchet 85 at the same in-- stant that latch 66 is pushed away from ratchet 41. Both curtains then move together and the full aperture CA passes across camera aperture Aand makes the required exposure.

For speeds slower than such as /5, /2,

and 1 second, a retarding mechanism is introduced, which is ,controlled by movement of the dial indicator 28. For the above speeds, the dial 21 is set at as, and the dial 28 may then be set at the selected slower speed.

A pin I05 (Fig. 16), eccentrically mounted in dial 28, projects through the housing top 26 and engages a lever I06, pivoted at I01 and having a slot I08 to permit longitudinal movement. Obviously, as pin I05 describes a circle, indicated at K in Figs. '7, 8, and 16, in being moved to various positions, the right end of I08 will be moved forward or backward or from right to left, and will on an intermediate member of a gear train 6..

This train is governed or retarded bya pallet I I1, the whole train being mounted in a frame I56 attached to the top Wall 24 of the camera. v An arm II8, pivoted at H9, is urged counterclockwise by a spring I20 so that its free end at I2I normally contacts a curved portion I22 on the free end of driver IIO. Inasmuch as spring II2 constantly forces driver I I toward the right, the latter is normally spaced away from ratchet I I5. Spring I20 is stronger than spring II2.

When the release lever 12 is swung to the left as button 14' is pressed, a hook I24 on said lever engages a square pin I25 on the end of arm H8 and thereby swings this arm to the left so that pin I25 is caught and held by a spring latch I26, pivoted at I21. Thus the end I22 of driver 0 is no longer obstructed and may be moved to the left against the action of spring I I2.

'When the button 14 is released, with the parts set as above described, the curtain FC moves a sufficient distance to bring aperture CA into register with camera exposure aperture A. This is accomplished in exactly a half revolution of cam ")0. The square pin IOI on gear 63 then contacts an abutment I28 on driver H0 and forces the entire driver toward the left (the pivot end being slotted as shown in Fig. '1) thus bringing rack II3 into engagement with ratchet II5. This movement of the driver IIO toward the left also causes its free end I22 to contact the free end of latch I26 and to disengage the latter from pin I25. Arm H8 is then swung counterclockwise by its spring II9 into contact with end I22 but cannot move driver IIO toward the right because of the continuing effort of pin IOI to force it to the left.

.free to be wound on foot roller pawl 60, have thus been returned to the starting point (one complete revolution) and the pawl 60 is again in engagement with shoulder 59 on ratchet 51.

Time exposures In operating the shutter for time exposures, the button 14 must be pressed and released, then pressed and released again. When the dial 28 is set for T'the pin I has been moved to its farthest travel toward the right, as shown in fragmentary view, Fig. 16. In this position, the downturned end I29 of regulating lever I06 abuts an upstanding lug I31 on rack H3 and prevents the latter from engaging the ratchet II5 at any point in the operation of the shutter.

When the shutter is wound and ready for release, with the parts set for time exposures as above described, the first pressure of button 14 moves release lever 12 and frees pawl 60 from shoulder 58 of ratchet 51 as in higher speed operations, and curtain FC passes over aperture A. Pin IOI strikes abutment I28 and thus aperture CA stops over exposure aperture A, as in Fig. 19. In moving the regulator I06 to farthest right position, a portion I38 thereon contacts a lug I39 on the lever H8 and swings'the latter clockwise against the action of spring I20, so that pin I25 rests in latch I26. The end I2I of I I8 then cannot interfere with movement of driver IIO toward the left.

A downturned lug I40 on driver H0 is so located that when the latter is in its normal position an end projection I4I on release lever 12 will pass said lug when the release lever is moved to the left as button 14 is pressed. After button 14 is released, the pin IOI has pushed driver IIO to the left (as in Fig. 8) the lug I40 will lie in the path of travel of end I4I. On the second pressure of button 14 this part I4I strikes lug I40, thus pushing the driver I I0 forwardly against the action of spring It2, carrying the abutment I28 past the pin IOI. The cam I00 is then free to complete the second half of its revolution as soon as button 14 is released. It is to be understood that curtain FC can never complete its movement and close aperture A until release lever 12 has swung to the right as the operator removes his finger from button 14. This movement then permits end 86 of the release lever to disengage pawl 83 from ratchet 85 leaving curtain FC 34. This latter holds true for all conditions of operation.

Delayed action The shutter as illustrated herewith is also. provided with a delayed action mechanism, whereby the operator may set the shutter and release the operating button, but the shutter will not be released until several seconds have elapsed, thus permitting the operator to take his own picture.

The gear. train I'I6 as shown in the sectional view, Fig. 13, has at one point a gear I44 that is freely revoluble on a shouldered portion of. a pinion I48. The latter is driven by a gear I49 I54, one end of which is attached to the shaft I50, the other end being attached to a stationary casing I55 which is fixed on the frame I56 that serves as a mounting for the entire gear train.

-When the spring I54 is wound as aforesaid, the pinion I48 is rotated counterclockwise (viewed from above). A spring washer I46, (Fig. 10) is staked to the shank of pinion I48 and therefore revolves with it, so that two toothlikepor tions I41 of the washer I46, which in effect constitute a double pawl, will pass over ratchet teeth I45 on the underside of gear I44. If now, the spring I54 is released, which may be accomplished as later described, the driving energy of the spring will be transmitted through gear I49, pinion I48 and washer I46, the teeth I41 of which will then engage the ratchet teeth I45 and will drive the gear I44 in a counterclockwise direction, and this gear will drive the rest of the train II6,'through to the governing pallet II 1. The extent to which the spring I54 is wound, or the are through which the operator moves the crank arm I53 in setting the delayed action determines the length of time the gear train will run and the relative speed of shaft I50. A full winding may run as much as or seconds depending on the design of the various members of the train,

Slow automatic exposures side pass freely over the spring ends l41of the washer I46.

The manner in which the retarded movement of shaft I50 is employed. to cooperate with the shutter release mechanism, whereby the latter is permitted to move and release the shutter at the end of the gear train operation, is as follows:

Fixed on the shaft I50, under pinion I5I, is a cam I51, (Fig. 11) of generally semicircular form, and having one substantially radial edge I58 that is beveled on its underside, and another edge I59, not beveled, that is, in the present structure, approximately 200 degrees of are from edge I58. At the unwound position of the delayed-action mechanism, the beveled edge I58 lies adjacent to an arm I60 that extends to the right and is part of release lever 12. As the operator moves the crank I53 clockwise, thus winding spring I54, the cam I51 rotates counterclockwise and the beveled edge I58 passes over the upturned end I6I of arm I60. The latter, being springy, will be depressed as the cam I51 rotates, but as soon as the cam has reached the fully wound position (Fig. 7) arm I60 springs up and its upturned end I6I blocks the cam I51 against rotation clockwise by contacting edge I59, and thus holds the,

spring I54 in wound condition. When the operator presses the button 14, the release lever 12 is moved to the left, as previously described, and the arm I60 is withdrawn from the edge I59 of the cam. The spring I54 immediately starts space of one tooth, or one'index numeral.

the gear train, the cam I51 begins to revolve clockwise, and as the operator releases the button 14 the lever 12 moves to the right'and the upturned end I6I of arm I 60 strikes and rides along on the semi-circular periphery of the cam, thus preventing the complete return of release lever 12. As the gear train revolves, this relation is maintained until the cam I51 has again reached the position of Fig. 12. The end I6I of arm I60 then slips past the edge I58, the lever 12 completes its return-movement, and in so doing, frees pawl 83 from ratchet 85 as previously described to make an exposure.

The bellcrank 91, constantly urged in a clockwise direction about its pivot 98, tends to carry the pin 99 into contact with the periphery of cam I00 at all times. During the unwinding of the shutter this is necessary, in order to release the curtain EC as required to establish the correct slit between edge G of FC and edge E of RC,

as previously described. On the clockwise or winding operation however, the pin 99 should be clear of the cam, and therefore a latch is provided, in the form of a bellcrank I65, pivoted at I69 (Fig. 15). A' pin I64, projecting upwardly from cam I00 (Figs. 2, 15, and 16) strikes the edge I66 of one arm of the latch I65 (Fig. 15) when the shutter is wound, and throws the other arm of the latch, which carries a hook I68, away from the cam. As the cam I00 makes one revolution counterclockwise on the release movement, the pin I64 strikes the edge I61 and swings the member I65 to the position of Fig. 16, so that hook I68 lies in front of pin 99 and prevents spring 91a from pressing said pin toward the cam. Pin 99 is thus held out from the cam until the shutter is again rewound, or until the cam is turned a full revolution clockwise, to the position of Fig. 15.

Exposure counter 29 is embodied in the camera which is operated automatically. This counter (Figs. 1 and 9) includes a calibrated dial I30, mounted in a suitable coverplate I3I and having ratchet teeth I32 onits under side corresponding to the calibrations.

A knob I33 projecting above the coverplate I3I permits resetting of the dial manually.

Step by step rotation of the dial I 30 is accomplished by a hook I34 on a slidable bar I35 that is suitably guided on the top 24 of the camera. A lug. I36 projects upwardly from this bar and is so located that it will be struck by the square pin IN. This pin strikes the right side of lug I36 when the shutter is wound-i. e., when the ratchet 51, carrying pawl with it, has been rotated 360 clockwise. carries the slide bar I35 toward the left, so that hook I34, in engagement with one of the teeth I32, rotates dial I30 the When the shutter is released, and gear 63 and pawl 60 have rotated 360 counterclockwise, the pin IOI strikesthe left side of lug I 36 and moves slide bar I35 to the right a sumcient distance to engage the next ratchet tooth of dial I30. Theslide bar I35 rests in this position until the shutter is again wound.

Summary of operation While the operationfof the various parts has been described, the operation of the shutter may be summarized as follows: If an operator desires position a fresh area of film and wind up the shutter curtains. By depressing the trigger' or push button 14 one curtain moves a distance necessary to make'the desired slot for the selected exposure and then stop. By releasing the trigger l4 permitting it to move upwardly both curtains are released so that they may move together across the exposure aperture A, the slot between them remaining constant and causing an exposure to be made.

If a delayed exposure is desired the handle I53 may be moved to set spring and the mechanism in running down causes an exposure to be made.

For short automatic exposures dial 2'? is set;

for longer automatic slow exposures of over 5 of a second, dial 21 is set to and dial 28 is set to the desired time, as second. The exposure is made as before by depressing button 14 to set the slit in the shutter and releasing the button to make the exposure.

With the button 14 described above which is released, instead of depressed as in known shutters, it is quite obvious that all tendency to shake the camera is eliminated since the operator is not overcoming tension on a spring at the instant an exposure is made. The movement of the button through its two paths for setting and releasing the shutter can be accomplished quickly and easily, and the tendency to movethe camera is eliminated.

, I claim:

1. In a focal plane shutter for cameras the combination with a pair of curtains, of separate spring rollers for the curtains, one for each curtain, a pair of pawls, one for holding each curtain against movement-apair of separately ro-' tatable members on which parts of each curtain are attached, and mechanisms for controlling the release of the pawls comprising a settable dial carried by the shutter, markings on the dial and shutter for indicating exposure, a pivoted lever adjustable by said dial forming a speed selector stop, a second pivoted lever, a cam operated by the first curtain for moving said lever, and a latch trip pivotally attached to the second pivoted lever and having an upturned end to engage the selector, whereby movement of the cam controlled lever may swing said tripping lever until drum, and coaxially arranged spools, one end of one curtain including tapes attached to the drums, and anend of the other curtan bein fastened to the drum, means for controlling the relative movement of the two curtains comprising a trigger, aholding pawl forone-curtain operated upon by the trigger, a second holding pawl for the other curtain, connections between the trigger operated pawl and the second pawl com-.

prising a speed adjusting dial carried by the camera, a timing cam carried thereby, a stop adapted to be set'by the cam, a pivoted lever carrying a swingable pivot, a floating lever carried by the pivot, said floating lever including two ends one adapted to strike the time controlling stop and the other to strike and release the sec- 0nd latch whereby one curtain may be released at a predetermined interval after the first curtain is released, and a cam operable by the first released lever for moving the swingable lever carrying the swingable pivot.

3. In a focal plane'shutter for cameras, the combination with two curtains, independent spring rollers, one for each curtain, supports for the opposite ends of said curtains including a drum, and coaxially arranged spools, one end of one curtain including tapes attached to the drums, and an end of the other curtain being fastened to the drum, means for controlling the relative movement of the two curtains comprising a trigger, a holding pawl for one curtain operated upon by the trigger, a second holding pawl for the other curtain, connections between the trigger operated pawl and the second pawl comprising a speed adjusting dial carried by the camera, a turning cam carried thereby, a stop adapted to be set by the cam, a pivoted lever carrying a swingable pivot, a floating lever carried by the pivot, said floating lever including two ends one adapted to strike the time controlling stop and the other to strike and release the second latch whereby one curtain may be released at a predetermined interval after the first curtain is released, a cam connected to the curtain which is released first to be operated one revolution thereby, said swingable lever contacting with said cam and adapted to be moved to and from a position in which the floating lever may be operative to release the second curtain.

4. In a focal plane shutter for cameras, the combination with two curtains, independent spring rollers one for each curtain, supports for the opposite ends of said curtains including a drum, and coaxially arranged spools, one end of one curtain including tapes attached to the drums, and an end of the other curtain being fastened to the drum, means for controlling the relative movement of the two curtains compristhe trigger operated pawl and the second pawl comprising a speed adjusting dial carried by the camera, a timing cam carried thereby, a stop adapted to be set by the cam, a pivoted lever carrying a swingable pivot, a floating lever carried by the pivot, said floating lever including two ends one adapted to strike the time controlling stop and the other to strike and release the second latch whereby one curtain may be released at a predetermined interval after the first curtain is released, a cam connected to the curtain which is released first to be operated one revolution thereby, the shape of said cam being such that said swingable lever is normally held in an inoperative position out of contact with the settable stop and second curtain pawl whereby said adjustable dial may be set at any time before or after an exposure has been made.

5. In a focal plane shutter for cameras, the combination with two curtains, independent spring rollers one for each curtain, supports for the opposite ends' of said curtains including a drum, and coaxially arranged spools, one end of one curtain including tapes attached to the drums, and an end of the other curtain being trigger operated pawl and the second pawl comprising a speed adjusting dial carried by the camera, a timing cam carried thereby, a stop adapted to be set by the cam, a pivoted lever carrying a swingable pivot, a floating lever caroperative position out of contact with the settable stop and second curtain pawl whereby said adjustable dial may be set at any time before or after an exposure has been made, and an edge included in said cam for rapidly moving the floating arm towards an operative pawl tripping position as said cam is turned by movement of the first released curtain.

6. In a focal plane shutter for cameras, the combination with 'a pair of flexible curtains, of

separate spring actuated rollers for winding eachcurtain, a pair of spaced spools, a shaft to which the spools are keyed, tapes connected to the spools and one curtain, a roller mounted freely on the shaft between the spools supporting the other curtain, separate holding ratchets for the spools and roller, separate pawls for engaging the holding ratchets, atrigger for releasing one holding ratchet, and means for releasing the other holding ratchet comprising a manual speed stop, suitable graduations to determine the position of said stop, a rotatable cam operable by the curtain released by the trigger and means op-' erated by the cam for tripping the second holding pawl including a floating lever including two oppositely disposed arms, a pivot carrying the lever between its ends, said means operated by the cam swinging said lever bodily until one end of the floating lever hits said stop and the other end trips the second holding pawl thereby releasing the second curtain a predetermined time after the first curtain is released by the trigger.

7. In a focal plane shutter for cameras, the combination with a pair of flexible curtains, of separate spring actuated rollers for winding each curtain, a pair of spaced spools, a shaft to which the spools are keyed, tapes connected to the spools and one curtain, a roller mounted freely -on the shaft between the spools supporting the other curtain, separate holding ratchets for the spools and roller, separate pawls for engaging the holding ratchets, a trigger for releasing one holding ratchet, and means for releasing the other holding ratchet comprising a manual speed stop, suitable graduations to determine the position of said stop, a rotatable cam operable by the curtain released by the trigger and means operated by the cam for tripping the second\holding pawl including a floating lever including two oppositely disposed arms, a pivot carrying the lever between'its ends, said means, operated by the cam swinging said lever bodily until one end of the floating lever hits said stop and the other end trips the second holding pawl thereby releasing the second curtain a predetermined time after the first curtain is released by the trigger, a friction clutch between the coaxially arranged spools and roller and means for tensioning the two curtains after an exposure has been made.

8. In a focal plane shutter for cameras, the combination with a pair of flexible curtains, of

separate spring actuated rollers for winding each curtain, a pair of spaced spools, a shaft to which the spools are keyed, tapes connected to the spools and one curtain, a roller mounted freely on the shaft between the spools supporting the other ourtain, separate holding ratchets for the spools and roller, separate pawls for engaging the holding ratchets, a trigger for releasing one holding ratchet, and means for releasing the other holding ratchet comprising a manual speed stop, suitable graduations to determine the position of said stop, a rotatable cam operable by the curtain released by the trigger and means operated by the cam for tripping the second holding pawl including a floating lever including two oppositely disposed arms, a pivot carrying the lever between its ends, said means operated by the cam swinging said lever bodily until one end of the floating lever hits said stop and the other end trips the second holding pawl thereby releasing the second curtain a predetermined time after the first curtain is released by the trigger, a friction clutch between the coaxially arranged spools and roller and means for tensioning the two curtains after an exposure has been made, including gearing connected to the roller, a pawl and ratchet for moving one of said gears in one direction only, and a handle for turning the gearing through the pawl and ratchet whereby the roller and spools may move as the former transmits movement to the latter through the friction clutch.

9. Ina focal plane shutter for cameras, the combination with a pair of curtains, a spring operated drum to which one end of each curtain is attached, a rotatable support for the opposite end of each curtain, separate pawls for holding the rotatable supports for each curtain against movement, a trigger for releasing the first curtain pawl and mechanism operated by movement of the first curtain for controlling the release of the pawl holding the second curtain, said mechanism including a speed adjusting dial carried by the shutter and movable to predetermine the speed of an exposure, a stop positioned by said dial and comprising a lever, pivotally mounted at one end, a flange at the other end forming a stop, and an operative connection between the lever and dial for moving the former by the latter, a floating lever pivoted intermediate its ends having one end adapted to be controlled by the dial, and means operated by the first curtain.

for swinging the pivot carrying the floating lever whereby one end thereof may strike said dial operated stop and the other end thereof may trip the second curtain pawl whereby the first curtain may precede the second gsurtain by a predetermined amount.

10. In a focal plane shutter for cameras, the combination with a pair of curtains, a spring operated drum to which one end of each curtain is attached, a rotatable support for the opposite end of each curtain, separate pawls for holding the rotatable supports for each curtain against movement, a trigger for releasing the first cur-, tain pawl and mechanism operated by movement of the first curtain for controlling the release of the pawl holding the second curtain, said mechanism including a speed adjusting dial carried by the shutter and movable to predetermine the speedof an exposure, a stop positioned by said dial and spaced from the second curtain pawl, ,a floating lever pivoted intermediate its ends and having one end adapted to be controlled by the dial, means for bodily moving the floating lever toward the dial stop and curtain pawl until the ends of the lever by striking the stop swings upon its pivot to release said second curtain pawl, the means includinga part moved by the rotatable support for the first curtain.

11. In a focal plane shutter for cameras, the combination'with a pair of curtains, a spring operated drum to which one end of eachcurtain is attached, a rotatable support for the opposite end of each curtain, separate pawls for holding the rotatable supports for each curtain against movement, a trigger for releasing the first curtain pawl and mechanism operated by movement of the first curtain for controlling the release of the pawl holding the second curtain, said mechanism including a speed adjusting dial carried by the shutter and movable to predetermine the speed of an exposure, a stop positioned by said dial and spaced from the second curtain pawl, a floating lever pivoted intermediate its ends and having one end adapted to be controlled by the dial, means for bodily moving the floating lever toward the dial stop and curtain pawl until the ends of the lever by striking the .stop swings upon its pivot to release said second curtain pawl, the means including a part moved by the rotatable support for the first curtain, whereby the floating lever may be moved only after the first curtain has moved, and-a spring for normally holding said floating lever out of the path of the dial stop whereby said dial may be adjusted either before or after an exposure is made.

12. In a focal'plane shutter for cameras, the combination with a pair of curtains, a spring operated drum to which one end of each curtain is attached, a rotatable support for the opposite 7 end of each curtain, separate pawls f r holding the rotatable supports for each curtain against movement, a trigger for releasing the first curtain pawl and mechanism operated by movement of the first curtain for controlling the release of the pawl holding the second curtain, said mechanism including a speed adjusting dial carried by the shutter and movable to predetermine the speed of an exposure, a stop positioned by said dial and spaced from the second curtain pawl, a floating lever pivoted intermediate its ends and having one end adapted to be controlled by the dial, means for bodily moving the floating lever toward the dial stop and curtain pawl until the ends of the lever by striking the stop swings upon its pivot to release said second curtain pawl, said means including a part movably connected to the first curtain rotatable support whereby movement of the first curtain swings the floating lever to trip the second curtain pawl after a time interval determined by the dial.

13. In a focal plane shutter for cameras, the combination with a shutter casing, of two curtains mounted therein, a separate spring roller for each curtain, a separate winding roller sup- 3 ends and means for swinging the pivot carrying the lever bodily froman inoperativeposition spaced from the second curtain pawl and the stop into a position to contact with these parts to trip the second curtain pawl, and connections between said means and said first curtain roller support.

14. In a focal plane shutter for cameras, the combination with a shutter casing of two curtains mounted therein, a separate spring roller for each curtain, a separate winding roller support for each curtain, separate releasing pawls for each curtain, a timing mechanism carried by the shutter casing and including an adjustable stop which may be inoved independently of the curtains for controllingthe relation between the curtains for an exposure, a trigger for actuating the first curtain pawl, a second curtain pawl tripping lever comprising a two armed floatin lever, a pivot supporting the lever between its ends, and means for swinging the pivot carryin the lever bodily from an inoperative position spaced from the second curtain pawl and the stop into a position to contact with these parts' to trip the second curtain pawl, and connections between said means and said first curtain roller support, said means being movable by the first curtain roller support to remove said floating lever to-its inoperative position after the second curtain pawl has been tripped.

JOSEPH MIHALYI. 

